高強度降雨形成之地表水入渗至土體後，造成土層內部孔隙水壓增加，是造成邊坡淺層崩塌主要原因之一。本研究主要以壓密理論為基礎，使用方型石柱探討土層表面受到動態壓密以及逕流水沖擊下，土層內部動態孔隙水壓力分布及傳遞之行為機制。實驗以均勻級配之礫石及玻璃砂，於不同土體厚度、夯實程度與撞擊能量下進行探討。實驗結果顯示土體受到動態壓密產生之動態孔隙水壓為逕流沖擊之10~20倍；厚度較長之土體，在同一能量撞擊時將產生一影響深度，於此深度產生較大之動態孔隙水壓，若土體小於此臨界厚度，則在土層底部產生較大之動態孔隙水壓；排列鬆散土層受到動態壓密時底部將激發較大之動態孔隙水壓；逕流沖擊土層造成表面捲增掏刷，且玻璃砂土層底部不透水層有向上排水之現象。 The rainfall induced infiltration increases the pore water pressure, and leads to cause the failure of the shllow slopes. This study experimentally examines the response of pore water pressure during the progressing of the wetting front for the talus. Both the impact from run-off and the variations of the dynamic water and seek slumping are considered pressure depend on porosity and the depth of soil and falling height of the run-off slumping block. The slumping block generates the higher dynamic water pressure than the impacting water. It is found that the soil layer has a improvement depth, which generates the maximum dynamic water pressure. When the soil layer is less than the improvement depth, the maximum dynamic pore pressure occurs in the bottom. When the run-off impact the soil surface, it causes the soil erosing wear for ground surface.
